Recently there have been many advances in the development of polymeric systems for delivering drugs. However, nearly all of these systems release drugs at decreasing or, at best, constant rates. Prior to this invention there has been no satisfactory means for increase in the release rates on demand nor has there been any way to control drug administration externally from the body once the release process has commenced from the implanted polymer-drug composition. It has been proposed to magnetically modulate drug delivery from implanted polymer-drug compositions by utilizing a composition that includes small magnetic beads imbedded in the polymer together with the drug. Release rates can be enhanced when desired by an oscillating external magnetic field. However, the extent to which release rates of the drug can be increased by the magnetic field has been unduly limited so that it is difficult to apply such a system to a patient who requires a relatively large dosage of drug within a short period of time.